The basic processes for obtaining useful color images from exposed color photographic silver halide materials include several steps of photochemical processing such as color development, silver bleaching, silver halide fixing and water washing or dye image stabilizing using appropriate photochemical compositions and automatic processing machines. Photographic color developing compositions are used to provide the desired dye images early in the photoprocessing method. Such compositions generally contain color developing agents, for example, 4-amino-3-methyl-N-(2-methane sulfonamidoethyl)aniline, as reducing agents to react with suitable color forming couplers to form the desired dyes
Traditionally, the color development process has required one or two days for providing the customer with the desired prints. In recent years, customers have wanted faster service, and in some locations known as “mini-labs”, it is desired to provide the customer with the desired prints within an hour. This requires the photoprocessing methods to be even faster, and reducing the processing time to within a few minutes is the ultimate desire in the industry. Much effort has been directed towards co-optimizing photographic film/paper and processes for very short processing times of two minutes or less.
Reduction in processing time of the “display” elements or color photographic papers has been facilitated by a number of recent innovations, including the use of predominantly silver chloride emulsions in the display elements. U.S. Pat. No. 4,892,804 (Vincent et al) describes conventional color developing compositions for use with high chloride photographic elements that have found considerable commercial success in the photographic industry.
Color negative films, however, generally comprise little or no silver chloride in their emulsions, and generally have silver bromide as the predominant silver halide. More typically, the emulsions are silver bromoiodide emulsions with silver iodide levels up to several mol percent. Such films require these types of emulsions because emulsions containing high silver chloride have not demonstrated sufficient light sensitivity to be used as camera speed materials although they have the advantage of being rapidly processed without major changes to the color developer solution.
When color negative films are processed using a development time of less than 120 seconds, non-neutral changes in color balance result. Specifically, the bottom layer is impacted more than the top layer so a film that yields balanced contrast between layers in a standard development cycle will produce unwanted contrast mismatches when processed through a shortened development time.
Methods to accelerate development of exposed silver halide grains, which enable higher photographic response with smaller silver halide grains and/or lower granularity, have been realized. For example, U.S. Pat. No. 4,912,025 describes the release of electron transfer agents (ETAs) for development acceleration without a concomitant granularity and fog increase. These type of compounds are commonly referred to as electron transfer agent releasing couplers or ETARCs. More recently, U.S. Pat. No. 5,605,786 describes a method of imagewise release of an ETA where an —O—CO—(T)n-(ETA) group is attached at the coupling-off site of the ETARC. In addition, U.S. Pat. No. 4,859,578 describes 1-aryl-3-pyrazolidinone ETAs in combination with a SMRC. Such compounds, however, are not record selective so this would not alleviate the contrast mismatch problem. The use of non-ballasted ETARCs often result in higher contrast in adjacent layers. A class of ballasted ETARCs is described in U.S. Pat. Nos. 6,110,657 of Lunt et al; U.S. Pat. No. 6,114,103 of Friday et al; and EP 1 111 458 A1 (published Jun. 27, 2001). None of these disclosures, however, utilizes electron transfer agents with shortened processing times.
U.S. Pat. Nos. 5,972,584 and 5,932,399 describe the use of certain electron transfer agents contained in the developer solution or coated in the film. U.S. Pat. No. 6,020,112 describes the use of electron transfer agents in shortened processing times when utilized in high chloride silver halide emulsions. U.S. Pat. No. 5,830,627 describes the use of a blocked electron transfer agent and a rapid processing cycle. When processed through a rapid developer containing a special additive, the electron transfer agent is released in a non-imagewise fashion and provides improved developability in the coated layer.
There is still a need for a method of developing films using rapid processing which does not result in unwanted contrast mismatches in the developed film.